Imported biomass for power generation under domestic resource constraints: trade-offs between cost, supply feasibility, and emissions in Japan

Abstract Many countries face structural constraints that limit large-scale deployment of solar and wind power, necessitating the import of alternative fuels to reduce emissions. Using a high-resolution capacity expansion and dispatch model (SWITCH-Japan), we assess the role of imported biomass under varying policy constraints and fuel price assumptions. Results indicate that imported biomass is not utilized when renewable deployment is unconstrained. However, under constrained scenarios, biomass imports rise substantially, reaching up to 15% of electricity supply by 2050 and increasing system costs by up to 32% relative to least-cost pathways. This corresponds to biomass demand exceeding 140 Mt yr −1 —far above current global trade levels—highlighting potentially severe supply constraints. While biomass provides firm capacity, it raises important environmental concerns, including life-cycle emissions, land-use impacts, and carbon debt, and competes directly with hydrogen and nuclear power sources. These findings suggests that imported biomass may offer a limited transitional contribution but is unlikely to serve a scalable long-term solution. This underscores the importance of maximizing domestic solar and wind deployment while maintaining alternative fuel options such as hydrogen and uranium.